VDR and gestational diabetes: The VDR gene (encoding as SNPs p.BsmI, p.ApaI, p.TaqI, and p.FokI), and, HNF1A gene (encoding as SNPs p.I27L, p.A98V, and p.S487N) were chosen because these genetic variants have been reported to be associated with type 2 diabetes, as well as GDM risk [12, 14–20].